Signaling system for railways.



L. H. THUL'LIEN.

SIGNALING SYSTEM FOR RAILWAYS.

AFPLIOATIOR' FILED AUG. 22, 1904. RENEWED FEB. 27, 1906. 1

1,109,880. Patented Sept-8, 1914 Lou sa. trnULL'nn, 'nnenwoon PARK,rnunsnvamanssrenon 'ro THE UNION swrrcniaszcnsn COMPANY, or swxssvann,PENNSYLVANIA, A conronarron or rnnn's'vrvanra.

' srenamive SYSTEM FOR amwns.

To allwh'o'initmayconcern:

Be .it known that I, LOUIS H. THULLEN, a citizen of the United States,residingat Edgewood Park, in the'county'of Allegheny and Stat-cotPennsylvania, have invented GGItalIIYIlE-W and useful Improvements inSignaling" y'stems [for Railways,of which the following is aspecification.

' j'My'invent-ionrel-ates to s1gnaling systems Y titres thereof inclaims.

for railways, and it is particularly adapted for use in connection withelectric-railways wherein'the track rails are employed'as a return pathforthe propulsion current used for the-car on vehi'cle motors; Iwill-(le scribe I a signaling system embodying-any invention and-= itsapplication to an electric railwayand then point out the novel fea- Th'eaccom'p'anying drawing is a diagrammaticirepresentation of a portion ofarailway: and a signaling system embodying my invention. 1 a

Referring now tothe drawing, A desig nates a portion of a railway havingits opposite lines of railsprovided with insulation a'at suitable pointsto form what are technically known in the art as track "or blocksections. I

D designates a generator for supplying through adinemonductor dpropulsion current for the motors carried by cars or vehi clestraveling'along the railway. The generator D- may be a direct currentgenerator or an alternating current generator. Each car or vehiclecarrying a motor is provided with a trolley (Z or other equivalentdevice which contacts with the conductor (1 as the car or vehiclestravel along the railway. The return for the propulsion current from themotors is through the track rails and to permit of this and thus savethe cost of line conductors or cables for this purpose, I provideinductive windings F, F, at each insulation point along the railway.These .inductivewindings and their arrangement are set forth in myapplication for patents filed- Februa-ry 5th, 1904, Serial Nos. 192,145and 192,146. It-is suflicient to here state that r the windings be soconstructed and arranged that the propulsion current of any descriptionwill freelv pass through them without appreciably afiecting them in anyway,while the alternating current for track circuit purposes will beimpeded and confined in its Specification of Iletters Patent. IApplication filed August 22, 1904, Serial No. 221,774. Renewed February2'2, 1906. SeriaYNo. 303,201.

ma a Sept. 8, 1914.

erated or controlled device which is 0on 'trolledfrom the track circuitof the track section: the drawings I have shown two railwa'y signals S,S each of which comand an automatically operated mechanism of anywell-known type. Each tracksection is'provided with a trackcircuit-which, as usual,-comprises a source of current, the op posite orportions of the opposite lines of rails and translating devices each inthe form of a relay which controls a local circuit. The source ofcurrent for each track circuit may be any desired and as here shown mmthe form of a transformer T to be hereinafter referred to. The primarywinding t of each transformer is in circuit with mains c,- 0 extendingalong the railway from an alternating signaling current generator A. 0.,while its secondary t is .connected with the track rails of itstrack andB may be of any desired construction .provided it is responsive to thecurrent intended for its operation. Preferably each translating devicewill be substantially of the form shownand described in my applicationfor patent filed October 13th, 1903, Serial No. 176,836. The localcircuit or other circuit which is controlled by the translating deviceincludes a source of current and the electrically operated or anelecnal. The source of current for the local circuitmay be any desired,and as here shown is obtained from the direct current generator D. Inthe event that alternating current is used forpropelling the, cars, thealternating signaling current will be of a different' frequency;

Heretofore in signaling systems and espe- One pole of the generatorprises a semaphore or other signal device trically controlled device ofthe railway-Sigsection. The translating device or relays R I ci'ally inblock signaling systems, it is usual to place the source of signalingcurrent at one end of the track section, usually at the exit end, andthe translating device or relay at the other or entrance end. In thepresent invention 1, preferaltily employ two translating devices R, It,for each track section and locate them preferably at or near the ends oithe track section and the source of signaling current'supply for thetrack circuit between the ends of the track sections preferably at apoint midway of the ends of the track section. The object in locatingthe source of current, in this instance the transformer T, between thetranslating'devices R, R is as follows In all track circuits it isdesirable that the amount of current and the E. M. F. thereof be kept aslow as possible on account of the leakage from the track rails and forother reasons economical and otherwise. Especially is this trueof-alternating current, for, as is well known, the track rails olferconsiderable impedance to. an alternating current which varies from 1 toan infi mte number of times the ohmic resistance,

depending upon the frequency otthe current. At ordinary frequency (from25 to 133 cycles) this impedance might approximately be 20 times theohmic resistance. Therefore by placing the supply .of alternatingcurrent at one end of a track section and the translating device at theother end thereof, a comparatively high-E. M. Rot alternating current isrequired at the source of current to supply the necessary E. M. F. to

operate the translating device. For exam-- ple, if the transformer is atoneend of a track section and the translating device at the other end,the A. C. potential at the transformer end will be from Gto 12 timesgreater than the A. C. potential at the other, and therefore, there is alikelihood of the insulating joints breaking down between two adjacenttrack sections, and the transformer furnishing current to thetranslating device in the adjacent track section. To overcome this andother objections I locate the source of alternating signaling current(in this case the transformer ata point between the translating devices,referably at a point midway of the, endso the track section. ll ith thisarrangement the high alternating E. M. F. or potential isatsubstantially the middle of the. track section and substantially thesame alternating current E. M. F. is obtained at the terminals of bothtranslating devices and, at the ends of the track section. l/Vith thisarrangement of the transformer a much lowerE. M. F. of alternatingcurrent could be used in the track circuit which is highly desirable, orthe length of the track section could be double at the same A. C.potential as used when the transformer is at one end of the block.

What I claim as my invention is:

' 2.111 a signaling system for'electric rail-- ways inwhich the trackrails are employed as a return path for the propulsion current, thecombination with a serles of insulated track sections, of inductivewindings arranged to be unaffectedby the passage of the propulsioncurrent from one track section to another but to afford a path of highimpedance to the passage of alternating signaling current, and a trackcircuit for each track section which comprises a source of alternatingsignaling current located between the ends of the track. section andadapted to deliver an alternating signaling current at the ends of thetrack section of lower potential than at its point of connectionwith thetrack rails of the track section.

3. The combination in a signaling system for electricrailways,-the-track rails of which are used as a return for thepropulsion cur rent, and are divided into insulated. sections,

of inductive windings for connecting the track rails of adjacent tracksections, a trackcircuit for each track section which com prises atleast two translating devices one eing located at about one end ofthetrack circuit and the other located. at about the other end of thetrack circuit and a source of alternating current, said source of,alternat ing current bein located at a point in the track circuit w'erebyj substantially equal alternating current potentials will besupplied the track rails of the track section at the terminals of eachinductive .winding at the ends of the track section.

a 4:. The combination in a signaling system for electric railways, thetrack rails of which are used as a return for the propulsion current andare divided into insulated track sections, an inductive winding at eachtrack section which permits. of the passage of the propulsion current,and a track circuit for each track section comprising at least tworelays one being located at about one end of the track circuit andtheother located at about the other end of the track circuit and a sourceof alternatingcurrent located in the track section at a point to producea higher alternating currentpotential between the track rails than thatproduced at the inductive windings at the ends of, the track section.

5. The combination in a signaling system for electric railways, thetrack ralls of which are used as a return for the ropulsion current andare divided into insulated track sections, inductive windings at eachtrack section which afiord a path of highv impedproduce a higheralternating'current poten-;

tial between the track rails than that produced at the inductivewindings at the ends of the track section.

6. In combination with a railway, the track rails of which are dividedby insulation into track sections and form a part of the return path forthe car propulsion current, a pair of inductive windings placed at eachinsulation point, one winding being connected with the track rails ofone track section and the other winding being connected with the trackrails at the adjacent track section, and the middle points of adjacentwindings beingelectrically connected, and a track circuit for each tracksection, each track section comprising a relay device to control arailway signal and a source of signaling current located at about themiddle point of the track circuit.

7. In combination with a railway the track rails of which are divided byinsulation into track sections and form a part of the return path forthe car propulsion current, a pair of inductive windings placed at eachinsulation point, one winding being connected with the track rails ofone track section and the other winding being connected with the trackrails of the adjacent track section, and the middle points of adjacentwindings being electrically connected, and a track circuit for eachtrack section comprising a source of alternating signaling currentlocated at a point in the track section to produce a higher alternatingcur-- rent potential between the track rails than that produced at theinductive windings .at the ends of the track section;

8. In a signaling system for electric railways, the combination with asource of power current, a transmission system therefor of which bothtrack rails form a part, a plurality oftrack sections, means forconducting the. propulsion current from the track rails of one tracksection to an adjacent track section, a source'of signaling current foreachblock section located at about the middle point of the blocksection, a railway signal for each block section, a control-,

ling means for said railway signal energized from the track, the energybeing taken from the track at one portion of theblo'ck section,

and a second controlling means'for; said railway signal energized fromthe track, the

energy being taken from the track at another portion of the block,section.

9. In a signaling system for electric railways, the combination with asource of power current, a transmission system therefor of whichbothtrack rails form apart, a plurality of track sections, means forconducting the propulsion current from the track rails of onetracksection to an adjacent track section,.a source of signaling current foreach block section, located at about the middle point of the blocksection, a railway signal for each block section, a controlling meansfor saidrailway signal at one end of a block section, a controllingmeans for the r ailwaylsignal' at the other end of the same blocksection, and both of said 'controlling means energized from the track bythe signaling current of the block section.

10. The combination in a'signaling system for railways, of trackcircuits formed in part by the track rails of the railway, a source ofalternating signaling current connected acrossthetrack rails and locatedabout the middle of the track circuit, two translating devices for eachtrack circuit and complet-- ing said track circuit, one translatingdevice being located at oneend of the track circuit and the othertranslating device being located at the other end of the track circuit,and railway signals, one railway signal being provided for each trackcircuit and controlled byboth translating devices of its track circuit.

11. In combination with an electric rail-' way, a source of powercurrent; vehicles opwhich the vehicles make moving contact, one

of which is formed by the track; signal-circuits of which the rails ofthe track form two sides; signal devices for each signal circuit onesuch signal device being located source of alternating signaling currentfor each signal circuit connected across the track-rails'andlocated atabout the middle of each signal circuit, and means for limiting thealternating signaling currents to the several signal circuits.

at about each end of the track circuit; a i

.13. In combination with an electric rail-,

way, a source of powercurrent; vehicles up 4 h 1109 sac erated' thereby;a circuitifor:said=powe12cur located at about the midiile of each-signalrent comprising two conductors: with which cimuit, and cross-bondslocated ,Mabmt the the vehicles-make meving contacts, one-10f each oftfiesignal circuits, which is formed by the track;vsignal circu its Intestimony whereof I have signed my 5 of which the rails of the trackform.twn namasto this s ecification in thwpmsenceof 15 sides;signaldevices for each signal circuit two subscribe 4 Witnesses.- onesuch signal dvice, being locatedlat about LOUIS H 'IHUILLELL- each endof the trackcirouit, a, source: of'af- Witnesses,

ternating signaling current for each signal GnohEh misza, 10 circuit,connected across'the trwckeralls .and-

WDGNHRi Gopie: of this-patent'may be owned for five cent: each, -by aidressfl1:lbw-commoner oz rmtentiy wuhlngtqu; ID. 0;?

